Reconfigurable circuits have been widely used in the semiconductor industry for field programmable gate arrays (FPGAs) and for repair of a defective memory element. The FPGA consists of a set of simple, configurable logic blocks in an array with interspersed switches that can rearrange interconnections between the logic blocks.
Reconfigurable circuits are also expected to play a significant role in three-dimensional integration technology that is being currently developed. Three-dimensional integration fabricates multilayer structures that can form a single chip combination with different functionalities. In these multilayer (and multifunctional) systems, reconfigurable circuit connection is typically needed to provide controllable logic functionality, memory repair, data encryption, as well as other functions.
Phase change materials are an attractive option for use in reconfigurable circuits. Devices with phase change materials, for example, are described in U.S. Patent Application No. 2007/0099405, filed by Oliva et al., entitled “Methods For Fabricating Multi-Terminal Phase Change Devices” (hereinafter “Oliva”) and in U.S. Patent Application No. 2007/0096071, filed by Kordus et al., entitled “Multi-Terminal Phase Change Devices.” (hereinafter “Kordus”). Specifically, Oliva and Kordus both describe multi-terminal phase change devices, for example, having two terminals located on opposite sides of the device from one another that are linked to the phase change material. Two other terminals control a heater that heats the phase change material to change the conductivity of the phase change material between different states.
A notable challenge that exists with regard to reconfigurable devices, in general, is that a large number of complex processing steps are typically required to produce the devices, which means high production costs and low production output. Thus, there exists a need for reconfigurable device technology that is more cost-effective and easier to produce.